Marijuana can help relieve the suffering of patients with diseases such as AIDS and cancer, but may also produce undesirable cognitive side effects. Investigation of these side effects is complicated by the fact that there currently are no standard efficient means for assessing cognitive impairment in the context of Marijuana research. We propose to develop a self-contained device for investigating such issues, the Marijuana Induced Neurocognitive Impairment System (MINIS). Prior work demonstrates that EEG and behavioral performance data are sensitive and specific indicators of level of alertness and ability to sustain attention. During Phase I, we will evaluate the feasibility of the MINIS by analyzing task performance and EEG data from subjects who have smoked a marijuana cigarette containing placebo or of delta9-THC. We will evaluate how well EEG and behavioral indices discriminate each subject's post-drug conditions from placebo. Additionally, we will determine what improvements are needed to our automated signal processing algorithms for use with measures of medication effects, and design modifications to a specialized system for administering, analyzing and tracking the tests and results. In Phase II the system would be implemented, validated and independently tested. PROPOSED COMMERCIAL APPLICATION The proposed system would serve as an enabling technology for researchers interested in objectively evaluating cognitive impairment occurring as a side effect of ingesting marijuana. With further development, it could become a clinical device for routinely assessing such effects.